XPS 15 9550 still throtles CPU on battery power?

Greetings!

I thought all my problems with CPU capping/throttling were gone with the BIOS update, but it seems they are not. So I'm wondering if the rest of you have this issue?
Just to make it clear, the infamous plug in/out CPU throttling problem is solved, but here the problem is with games in particular.
On battery power, CPU works normal under heavy workloads like rendering or doing tests like cinebench (AC like CPU frequencies - around 3GHz). But when playing a game - interestingly, not in the menus, but the moment graphics start - the CPU throttles and goes in the 0.5-0.8GHz range with occasional spikes up to 1.6GHz. I have tried it in many games, so it's not specific to a certain game or engine. And as soon as I plug the charger back in, both CPU frequency and FPS go up. It's not thermal throttling because the temps hardly reach 50°C (~120°F).
I know that 1.6GHz was the previous cap, but I'm baffled as to why the cap (if you can even relate this to the 1.6GHz cap, seeing how CPU mostly operates around 0.7GHz) is still present in games and not other instances, because it makes for an unplayable experience.
I have tried switching power profiles and increasing "Minimum processor state", but nothing helps. I guess disabling SpeedStep would solve the issue, but that's not much of a solution at all...

P.S. I have the FHD, i5 version with BIOS 1.1.19.

 

Use ThrottleStop. Check what the limit reason is. Post back.

 

The obvious didfference then is that the nVidia GPU starts working.

 

I'm not sure if I'm doing everything right, never used throttlestop before... I've just ran the program and set it to log while I game, don't know if I'm supposed to do anything else. Although when I enter Throttlestop, "Limit reasons" option is greyed out and I can't click it. I've selected the option to log limit reasons but it doesn't log it. Power is the last column, and there is nothing right to it. I'm using the 8.10 version.

 

I think the throttling is associated to the setting within Dell Command Power Manager. Set the temperature settings to optimized, cool or speed and restart the PC.

I set it to quiet once and I think that limited the laptop to 1.6GHz.

 

I don't have Dell Command Power Manager installed. And it doesn't show it as available for my service tag on the dell site.

 

Apparently you haven't tried hard enough. There is a button below the listed drivers of the DELL driver website (Alle Treiber für XPS 15 9550 durchsuchen <-> browse all XPS 15 9550 drivers).

http://www.dell.com/support/home/de...-15-9550-laptop&languageCode=ge&categoryId=UT

 

One would think that when I enter my service tag it would list all of the apps and drivers that apply to my model. But apparently it doesn't...
I've installed the Power Manager and changed it to Ultra Performance and it is still the same. Cpu throttles just like it used to. But thanks for the Power Command, some of these things I used to change in BIOS, this is more convenient.

 

I saw your thread and decided to check whether I have the issue as well. It appears my CPU (i5) also caps at the same freq as your does. Never noticed it before because I usually keep it plugged in when gaming. I have no idea what could be the cause, maybe as someone suggested that might be the point where the GPU kicks in. Although if a dedicated GPU is assigned to a certain executable it should switch to it as soon as the .exe is loaded.

 

It was the same for me. Always played games on AC, but I forgot to plug it in and started playing to find the performance deteriorate completely. At first I thought the GPU was the issue, but I found the GPU runs the same on battery and on AC. Didn't even think CPU was throttled because I've worked on battery and CPU never capped. Really strange.

 

> At first I thought the GPU was the issue, but I found the GPU runs the same on battery and on AC

That's not the point. BIOS might throttle the CPU for various reasons, one of them overall power consumption and heat when the GPU kicks in. That's why it would help to first indentify the cause - is it only when the GPU is used? Then one can test more accurate and also ask speciifc questions to Dell.

 

Yes, it throttles only when GPU kicks in. I've tested it a bit more:

As you can see, even when GPU starts working the multiplier is high. But 5 seconds after the GPU starts really working (what I believe is the moment when the game from menu goes to the actual gameplay), the multiplier drops.
I did the same thing with Photoshop running on dedicated GPU and no throttling. The differences from what I can tell are:
- Lower temps, but not by huge margin, maybe 10°C at most, both are still under 65°C
- Much lower GPU usage %
- Much lower memory usage
Albeit, I must add, I managed to get GPU to work hard in Photoshop by adding tons of filters on a huge image. For about 15 seconds, the core and memory clocks, as well as GPU usage went up just like when gaming. The CPU didn't throttle.
From what I can tell, what throttles the CPU is either:
- GPU memory usage (which never got nearly as high as in games)
- GPU Temperature (although it wasn't so high, and still doesn't explain why it throttles only on battery and not on AC)
- The fact that games are 3D, maybe throttling is set up to start only when GPU manages 3D applications. That would explain no CPU throttling in menus and almost immediate throttling as soon as the actual game starts.

 

Thanks for that, very informative!